Recent tensions about world oil supplies have put a spotlight on wind and solar power. After all, both are renewable energy sources, found within every nation's borders.

Harnessing this energy can be costly. But, scientists at the National Renewable Energy Lab in Golden, Colorado, are working to make the sun and the wind as affordable as more traditional energy sources.

"I like to pass these around. They're very thin," said scientist Ed Witt.

The glittery blue wafer in Ed Witt's hand is no larger than a greeting card. But photovoltaic cells such as these are mighty, they can power everything from solar calculators to satellites. To demonstrate the latest technologies, Mr. Witt leads me to an outdoor testing site.

"Here you're going to see arrays made of a lot of different kinds of solar cells, and we're going to have a little walk down through here," he said.

We amble past rows of solar panels, some developed here, and some sent to Golden by companies that collaborate with N-REL. Many use new thin-film methods, which are more economical than traditional wafers. And one display looks like shiny roof tiles, because that's what they are shingles that double as solar collectors.

"If we were standing 15 feet away, or it was on a roof that was above us, we might never notice that it's anything other than shingle material," said Mr. Witt.

It takes millions of dollars to research the materials and processes needed to make products like these affordable. But that's what the National Renewable Energy Lab in Golden, Colorado is all about. N-REL is the only national laboratory in the United States dedicated to research and development of renewable energies. It's also the premiere renewable energy research facility in the world.

"That's important because the world looks to us," Mr. Witt said. "They say, wow! What is the U.S. doing, and what is the National Lab for the U.S. doing? And it's what we're doing here. And so it's extremely important, Both from the point of view of lending credence to the technologies themselves, but it's also important in terms of sort of being the leader and moving in that direction."

When this laboratory was established in 1977, its scientists focused on solar power. Now, the more than 1,000 researchers and staff at N-REL develop everything from wind power to biomass technology, which involves using organic waste products to create clean-burning energy. And, Mr. Witt says, in the last 25 years they've gotten much closer to their original goal of harnessing solar power.

"The cost has come down by factors of certainly more than ten, probably about a hundred during that time," he said.

While solar power still has a way to fall before matching the price of energy produced from oil, Mr. Witt believes that in 30 years, the sun could provide 10 percent of the world's energy.

"Most of the modern windmills look much, much more like rotating airplane wings," said Bob Thresher, director of N-REL's Wind Technology Center. He says the sleek blades on his majestic wind machines can be as long as the wings on a passenger jet, and one machine can generate over a megawatt of power enough to supply all the electricity for 500 homes, day in and day out.

"Wind energy is the most rapid growing form of energy in the world at this point. In the last three years, it's grown at an average rate of about 30 percent per year," he said.

Mr. Thresher says many European countries are ahead of the United States in this field, because they tax fossil fuel use heavily, then subsidize their wind power programs. But he believes N-REL's efforts can make wind power competitive in America's more unregulated energy marketplace.

As the N-REL scientists develop these renewable sources of energy, Ed Witt says they are also laying the groundwork for a more peaceful world.

"All people need security, and this is a source of security for all of us. Independent of what your beliefs are or what cultures you come from," he said. "Here's a place where you can get the energy that you need in order to be self-sufficient."

With international collaboration in clean renewable energy projects, the National Renewable Energy Lab is helping dozens of other nations reach that goal.